A singular perturbation (SP) control method based on a high-order fully actuated (HOFA) model is proposed for permanent magnet synchronous motor (PMSM) position servo systems, which aims to address parameter uncertainties and external load disturbances while achieving fast response and high control accuracy. First, a HOFA model of the PMSM servo system is established. Then, the SP theory is used to reduce the order of the full-actuated model, and controllers for the fast and slow subsystems are designed based on the HOFA theory to suppress high-order differential noise. Next, to address the parameter perturbations and load disturbances in the system, a dynamic position feedback compensator is designed for the slow subsystem. Meanwhile, a differential tracker is employed as an input signal processing module to enhance the engineering applicability and tracking performance of the control algorithm under slowly varying reference inputs. Finally, simulation and experimental results demonstrate that the proposed method can effectively suppress the effects of unknown time-varying loads and parameter uncertainties, thereby enhancing the control accuracy of the PMSM position servo system.